There is known a screw type method of rotating a screw having a helical blade, which is axially provided over a surface of a rod-like member, such that the blade feeds a liquid material to an discharging port with rotation of the screw, to thereby discharge the liquid material. The screw type method is widely used, in particular, to discharge a highly-viscous liquid material and a liquid material containing a filler.
A known screw type discharging apparatus is disclosed, for example, in Japanese Patent Publication No. Hei 5-11513 (Patent Document 1). Patent Document 1 discloses an discharging apparatus comprising a cylinder in which a screw rod is inserted, the cylinder having a nozzle projected at the liquid outlet side and a supply hole formed, for introducing a liquid, on its lateral surface opposite to the liquid outlet side, and a reservoir coupled to the supply hole. The liquid introduced in a pressurized state through the supply hole is fed to the liquid outlet side with rotation of the screw rod, and the liquid is discharged onto the surface of a workpiece from the nozzle as per setting. Thus, a generally known method is designed to introduce the liquid in a pressurized state to the apparatus and to discharge the liquid with the screw rotation.
Further, as a method and an apparatus for accurately discharging a liquid containing a filler, the applicant has proposed a liquid material discharging method and apparatus comprising a screw having a helical vane which is provided on a cylinder surface to axially extend from a cylinder distal end, a rotation driving mechanism for rotating the screw, a main body having a liquid inlet port to which a liquid material is supplied, a screw penetrating bore through which the screw penetrates, and a housing which covers a distal end of the screw at the discharging port side thereof, and a nozzle mounted to a distal end of the housing and communicating with the interior of the housing, wherein a gap is left between the screw and an inner wall surface of the housing (Patent Document 2).    Patent Document 1: Japanese Patent Publication No. Hei 5-11513    Patent Document 2: Japanese Patent Laid-Open No. 2002-326715